Method of filling a hollow ballast ring with demagnetized material



R. S. GAUGLER METHOD OF FILL Feb. 14, 1961 2,971,546

ING A HOLLOW BALLAST RING WITH DEMAGNETIZED MATERIAL Filed Oct 18, 1957 Z440 His Afforney METHGD F FILLING A HOLLOW BALLAST RING WITH DEMAGNETIZED MATERIAL Richard S. Gaugler, Dayton, Ohio, assignor to Generai Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Oct. 18, 1957, Ser. No. 691,058

1 Claim. (Cl. 141-11) This invention relates to the method of and apparatus for filling the ballast rings of centrifuging devices without creating voids in the ballast ring during the filling process.

In the manufacture of centrifuging devices, such as the spin tubs for laundry appliances, it is customary to include a ballast ring for minimizing vibrations during the spinning operation. One type of ballast ring is formed on the tub itself by leaving a hollow chamber about the periphery of the tub. In order to obtain the necessary mass for stabilizing tub spin operation, this hollow chamber is filled with a ballast material during the tub assembly process. One filler or ballast material, magnetite ore, has been found to possess density and flow characteristics that facilitate both assembly and operation of the spin tub. However, considerable dithculty has been encountered in eliminating the voids incorporated in the ballast ring during the filling process. These voids result in uneven ballast distribution and prevent a smooth, vibration-free tub spinning operation. This difiiculty, it was found, resulted from a magnetized condition which exists in magnetite ore in its natural state.

Accordingly, it is an object of this invention to provide an improved method of filling a chamber with a granular material having magnetized characteristics.

It is a further object to provide a method whereby the assembly of ballast rings on laundry appliances is facilitated.

More particularly, it is an object of this invention to demagnetize a granular material prior to the filling operation of ballast rings and to provide apparatus for the demagnetizing process.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown. a

In the drawing:

The sole figure is a partly diagrammatic elevational view, with parts broken away, in which a preferred embodiment is shown of the apparatus necessary to practice this invention.

In accordance with my invention, a laundry tub of the centrifuging type is shown generally at 10. The tub is equipped with a ballast ring 12 forming the opening of the tub 10. The ballast ring has a hollow configuration so that it may be filled with a ballast material 14. In the embodiment set forth in the drawing the ballast ring is shown having a rectangular cross-section formed at one edge of a single sheet of metal 16 which is secured at its other edge 18 to the upper periphery of the bottom portion 20 of the tub 10. At one point on the upper surface22 of the ring 12 an opening 24 is provided as an access means for the ballast filler. The opening 24 is closed by any suitable means (not shown) after the ballast ring has been filled.

2,971,546 Patented Feb. H4, 1961 During the assembly of the tub 10, the ballast ring portion 12 is joined to the bottom portion in any acceptable manner. The tub assembly 10 is then placed upon a conveyor line (not shown) with the opening 24 uppermost, as shown in the drawing.

The apparatus for dispensing the ballast material during the assembly process includes a reservoir or container 28 and a conduit 36 having a nozzle portion 32. A valve 33 may also be included to regulate the flow of ballast filler at nozzle 32. Surrounding the conduit 30 at any point between the container 23 and the nozzle 32 is an induction coil 34 supplied with an alternating current from a suitable power source, L L The reservoir 28 is placed so that the ballast material 14 will flow through conduit 3% by means of gravity to the nozzle 32 and thus to the ballast ring H.

In operation, container 28 is loaded with a quantity of ballast filler 14, such as magnetite ore. However, it is to be understood that the flow characteristics of any granular substance having a natural magnetism would be improved by the teachings of this invention. As each laundry tub is presented to the ballast filling station, nozzle 32 is thrust through opening 24 in the top of the ballast ring. Valve 33 is then opened and the ballast material permitted to flow by gravity from the container 23 to the opening 24- and then by gravity again to the lower portion of the tilted ballast ring. Initially, the ballast filler 1 will flow around the circumference of the annular chamber to a point at 35. It will continue to fill the cavity until the ring is filled solidly to the opening 24. The valve 33 is then closed, the nozzle 32 removed, and the opening is closed. During the filling process, the induction coil 34 is continually energized by a strong alternating current from power source L L As the magnetite ore or other ballast filler 14 flows through the core of the induction coil it is: subjected to a strong demagnetizing force. Thus, the ore leaves the field of the induction coil in a completely demagnetized condition and flows freely into and around the ballast chamber 12. In this demagnetized condition the ballast granules have no tendency to attract each other and voids are thereby eliminated during the filling process. By analogy, the flow characteristics of a magnetized granular material can be compared favorably to the flow characteristics of wet sand. However, a demagnetizing process will alter the flow characteristics of this granular material to that of dry sand and thus provide a filler which will flow quickly and completely into any cavity to be filled.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claim which follow.

What is claimed is as follows:

A method of filling an annular ballast ring having an annular chamber therein and an inlet port in the ring to the chamber, comprising the steps of, tilting the ring in a position to place the inlet port uppermost, initially passing a maguetizable granular material of substantially uniform size through an alternating magnetic field to demagnetize the granular material, and subsequently causing the demagnetized material to flow into the inlet port until the ring is completely and homogeneously filled with granular material.

References Cited in the file of this patent UNITED STATES PATENTS 2,678,130 Onstead et al. May 11, 1954 2,807,363 Hendrickson et al Sept. 24, 1957 2,836,083 Smith May 27, 1958 

